Changes rewriteBasePath core config deprecation level to warning (#…

…114566)

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

src/core/server/config/deprecation/core_deprecations.test.ts

@@ -54,7 +54,7 @@ describe('core deprecations', () => {
 
   describe('rewriteBasePath', () => {
     it('logs a warning is server.basePath is set and server.rewriteBasePath is not', () => {
-      const { messages } = applyCoreDeprecations({
+      const { messages, levels } = applyCoreDeprecations({
         server: {
           basePath: 'foo',
         },
@@ -64,6 +64,11 @@ describe('core deprecations', () => {
           "You should set server.basePath along with server.rewriteBasePath. Starting in 7.0, Kibana will expect that all requests start with server.basePath rather than expecting you to rewrite the requests in your reverse proxy. Set server.rewriteBasePath to false to preserve the current behavior and silence this warning.",
         ]
       `);
+      expect(levels).toMatchInlineSnapshot(`
+        Array [
+          "warning",
+        ]
+      `);
     });
 
     it('does not log a warning if both server.basePath and server.rewriteBasePath are unset', () => {

src/core/server/config/deprecation/core_deprecations.ts

@@ -16,6 +16,7 @@ const rewriteBasePathDeprecation: ConfigDeprecation = (settings, fromPath, addDe
         'will expect that all requests start with server.basePath rather than expecting you to rewrite ' +
         'the requests in your reverse proxy. Set server.rewriteBasePath to false to preserve the ' +
         'current behavior and silence this warning.',
+      level: 'warning',
       correctiveActions: {
         manualSteps: [
           `Set 'server.rewriteBasePath' in the config file, CLI flag, or environment variable (in Docker only).`,